This invention relates generally to vascular access devices and methods, including catheter assemblies and devices used with catheter assemblies. Generally, vascular access devices are used for communicating fluid with the vascular system of patients. For example, catheters are used for infusing fluid, such as normal saline solution, various medicaments, and total parenteral nutrition, into a patient, withdrawing blood from a patient, or monitoring various parameters of the patient's vascular system.
A common type of intravenous (IV) catheter is an over-the-needle peripheral IV catheter. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. At least the inner surface of the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitate insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient's skin. The catheter and introducer needle are generally inserted at a shallow angle through the patient's skin into a blood vessel.
In order to verify proper placement of the needle and/or catheter in the blood vessel, the clinician generally looks for confirmation of the access. This confirmation may be dependent on good venting of the catheter adapter. Once proper placement of the catheter into the blood vessel is confirmed, the clinician may apply pressure to the blood vessel by pressing down on the patient's skin over the blood vessel distal of the introducer needle and the catheter. This finger pressure occludes the vessel, minimizing further blood flow through the introducer needle and the catheter. This is not always possible due to different reasons like: no time available, difficult vein, or lack of experience. In some other situations the clinician may need additional vein access confirmation in the catheter adapter and for that reason allows blood flow into the adapter.
The clinician may then withdraw the introducer needle from the catheter. The introducer needle may be withdrawn into a needle tip shield or needle cap that covers the needle tip and prevents accidental needle sticks. In general, a needle tip shield includes a housing, a sleeve, or other similar device that is designed such that when the needle is withdrawn from the patient, the needle tip will be trapped/captured within the needle tip shield. The purpose of the needle tip shield is to prevent clinicians from unanticipated blood exposure from needle sticks and other exposure from blood collected on or in the needle tip.
In devices where blood travels to the needle tip shield, an operator of the needle tip shield may be exposed to the blood when the needle tip shield is removed from the catheter adapter. Thus, various systems and methods are needed to provide needle tip shields that interface with other vascular access devices such as catheters, minimize exposure to and contamination by blood contained in, on, or around the needle tip shield, and/or provide blood flashback at least to the point of the needle tip shield within the catheter adapter.